1. Technical Field
The present invention relates to an optical receiver circuit used in optical communication.
2. Related Prior Art
A variety of transmission rates of optical signals are stipulated in transmission standards for optical communication. In recent years, there are demands for optical receiver circuits capable of receiving an optical signal with a variable transmission rate, i.e., optical receiver circuits applicable to multi-rate communication.
Receivers applicable to multiple transmission rates are known in the field of wireless communication. For example, the receiver disclosed in U.S. Pat. No. 6,584,304 is provided with sets of a filter and an amplifier for the respective transmission rates to receive radio signals. A switch for determining the destination of a radio signal is installed ahead of the filters and amplifiers. The operation of this switch is controlled according to the transmission rates, thereby supplying a radio signal to the filter and amplifier set suitable to the transmission rate of the radio signal. However, when the technology described in the patent document 1 is applied to optical receiver circuits, received data are lost during deciding the transmission rate and while changing the state of the switch.
Therefore, an object of the present invention is to provide an optical receiver circuit capable of receiving an optical signal with a variable transmission rate without loss of data.